Hi bucket, 180 means there are two holes at the top approximate center of the forward and rearward (almost at top but physically on the side), sides of the batteries. The rear hole should be plugged, the front one houses the 'push-on' small (old style cigarette lighter sized) vent, that vents battery gasses when charged. Without those two holes plugged (rear one plugged, front one a vent inserted), the gasses/overflow runs down to the tray and does damage to things like a hose, and other corrosion. Discussed in depth in posts, best to either install the ones off your old battery, or find them if not included with your new battery (as a note, I have never seen the vent accessory included with a new battery, only one 'plug'. Hope this helps!

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